Crude glycosides of Gymnocladus dioica have been shown to have antifertility activity in the rat at about 12.5 micrograms (MED 50) and 25 micrograms (MED 100) by intrauterine administration. The acute oral toxicity of this material has been shown to be above 1000 mg/kg in the mouse. The crude glycosides have been fractionated chromatographically and both active and inactive fractions have been found. Mild acid hydrolysis of the crude glycosides gives an aglycone mixture, of which one of the major components is a pentahydroxy pentacyclic triterpene acid. Although the complete structure of this acid has not yet been determined, it seems to be a compound that has not yet been reported in the literature. The oral antifertility activity of the crude fruit extract of Momordica charantia has been confirmed in the mouse at a level of 2 mg/day, which caused a decrease in pregnancy from 78% to 22%. The activity was suprisingly not found in the leaf extract, the glycosidic fraction of the fruit extract, or the also reportedly active leaf extract of the related Momordica balsamina.